Adding another TLD to dnsmasq installed with Laravel Valet

I've got Laravel Valet set up on my Mac (Monterey 12.5.1) to run PHP based sites locally on the .test TLD. This all works as expected and everything is fine.

I'm trying to set up another fictional TLD (.6d) to point to a server on my LAN (say 192.168.0.100). I've tried what I understand to be the normal way of adding this in dnsmasq - by adding a file called 6d in /etc/resolver with the following content:

nameserver 192.168.0.100

However, this doesn't seem to be working.

If I ping a domain on the server, I get (after a long pause):

ping testdomain.6d
ping: cannot resolve testdomain.6d: Unknown host

I'm not sure if this is a dnsmasq issue, or something that has arisen from dnsmasq being installed and configured by Valet - I have added the IP and domain to my /etc/hosts file in the traditional way and that works correctly, so I am sure the issue isn't the connection to the server itself.

The output of scutil --dns is:

DNS configuration

resolver #1
  nameserver[0] : 194.168.4.100
  nameserver[1] : 194.168.8.100
  if_index : 6 (en0)
  flags    : Request A records
  reach    : 0x00000002 (Reachable)

resolver #2
  domain   : local
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300000

resolver #3
  domain   : 254.169.in-addr.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300200

resolver #4
  domain   : 8.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300400

resolver #5
  domain   : 9.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300600

resolver #6
  domain   : a.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300800

resolver #7
  domain   : b.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 301000

resolver #8
  domain   : test
  nameserver[0] : 127.0.0.1
  flags    : Request A records, Request AAAA records
  reach    : 0x00030002 (Reachable,Local Address,Directly Reachable Address)

resolver #9
  domain   : 6d
  nameserver[0] : 192.168.0.100
  flags    : Request A records
  reach    : 0x00020002 (Reachable,Directly Reachable Address)

DNS configuration (for scoped queries)

resolver #1
  nameserver[0] : 194.168.4.100
  nameserver[1] : 194.168.8.100
  if_index : 6 (en0)
  flags    : Scoped, Request A records
  reach    : 0x00000002 (Reachable)

resolver #2
  nameserver[0] : 194.168.4.100
  nameserver[1] : 194.168.8.100
  if_index : 12 (en1)
  flags    : Scoped, Request A records
  reach    : 0x00000002 (Reachable)

So it looks like the 6d TLD is being picked up somehow... it just seems unable to resolve correctly.

Any ideas what I could be missing? Thanks.