Defining wildcards for hostname to redirect

You need to think through your goal.  Here is what is possible and appropriate.

DNS

DNS Wildcards do not exist because they should not exist.    No one says "Connect me to any old server as long as it is somewhere in example.com"

The user specifies a host name or an IP address to indicate where they want to go.   If the host name exists, it is converted to an IP address.   If the host name does not exist, the DNS Server return NXDOMAIN - non-existent domain.    This is the way DNS works.

There is a "default" name.    You can create a host record under example.com without a host qualifier but with an IP address.   This allows the unqualified name "example.com" to act like a host name.  It is commonly used to make the "www." part of a URL optional.   But this is still very different from a wildcard.  If you type "SurpriseMe.example.com", and SurpriseMe does not exist as an DNS record (A, AAAA, or CNAME) you will not get the default entry, you will get NXDOMAIN.

Web Filtering (outbound)

You can define a WebSite object and check the box "Apply to subdomains".    This will apply the category, reputation, or tag that you define with both the named domain and any first-level subdomains of that name.    It is very useful, but it does not apply to levels below the first one.   It also has nothing to do with traffic routing, it only applies to whether a site should be allowed or blocked.

Web Sever (inbound)

WAF supports Server Name Indication (SNI).   SNI allows multiple websites to exist on the same IP and port because the receiving website is able to route traffic based on the host name in the URL.   WAF actually supports a default website for an IP-Port pair, and I think it uses asterisk as the default indicator - check the help.  I have used SNI with WAF but have not used wildcard WAF sites.   The default site will also be used for URLs that contain an IP address instead of a name.

However, WAF still will not act as a catchall for a name that does not exist in DNS.   The client has to convert a name to a number in order to send a packet.   It cannot send a packet to a destination without an address.    The SNI function only works after the packet is received, so WAF can only receive a packet for SurpriseMe.example.com if the DNS contains a name-to-number lookup result for SurpriseMe.example.com

You need to think through your goal.  Here is what is possible and appropriate.

DNS

DNS Wildcards do not exist because they should not exist.    No one says "Connect me to any old server as long as it is somewhere in example.com"

The user specifies a host name or an IP address to indicate where they want to go.   If the host name exists, it is converted to an IP address.   If the host name does not exist, the DNS Server return NXDOMAIN - non-existent domain.    This is the way DNS works.

There is a "default" name.    You can create a host record under example.com without a host qualifier but with an IP address.   This allows the unqualified name "example.com" to act like a host name.  It is commonly used to make the "www." part of a URL optional.   But this is still very different from a wildcard.  If you type "SurpriseMe.example.com", and SurpriseMe does not exist as an DNS record (A, AAAA, or CNAME) you will not get the default entry, you will get NXDOMAIN.

Web Filtering (outbound)

You can define a WebSite object and check the box "Apply to subdomains".    This will apply the category, reputation, or tag that you define with both the named domain and any first-level subdomains of that name.    It is very useful, but it does not apply to levels below the first one.   It also has nothing to do with traffic routing, it only applies to whether a site should be allowed or blocked.

Web Sever (inbound)

WAF supports Server Name Indication (SNI).   SNI allows multiple websites to exist on the same IP and port because the receiving website is able to route traffic based on the host name in the URL.   WAF actually supports a default website for an IP-Port pair, and I think it uses asterisk as the default indicator - check the help.  I have used SNI with WAF but have not used wildcard WAF sites.   The default site will also be used for URLs that contain an IP address instead of a name.

However, WAF still will not act as a catchall for a name that does not exist in DNS.   The client has to convert a name to a number in order to send a packet.   It cannot send a packet to a destination without an address.    The SNI function only works after the packet is received, so WAF can only receive a packet for SurpriseMe.example.com if the DNS contains a name-to-number lookup result for SurpriseMe.example.com

What I want to configure is the routing via traefik.
What traefik does is routing requests to services that need to deal with them.

For this I need several hostnames. I want to redirect all hostname requests with a certain subdomain to one IP address.
For example, I want to access a.dev.xyz and b.dev.xyz with one rule if possible, because there are many more services to redirect.
For now I have added additional hostnames manually and I don't want to do this that way, or is there another solution?

Edit:

I have created a DNS Host with a wildcard e.g. (*.dev.xyz.com) and it says it's resolved. Can I further create a NAT rule to route with it?
For now i have chosen ANY.

Externally I can connect to traefik and my services.
But if i want to connect to e.g *.dev.xyz.com within my network it fails.

I have looked at traefix superficially, but I think I understand this part of its design.

The point of a load balancer is to capture traffic for one hostname/IP address and redirect it to an available pool of backend systems based on available capacity or other rule.   You do not use wildcards at all.