In my case, I found that it was due to the clipboard loading. Here are the steps and fix.
# terminal 1
vim --startuptime vim.log
# terminal 2
less vim.log
# "setup clipboard" step took > 30 seconds
...
32003.362 31928.192: setup clipboard
...
# reference .vimrc for the fix
For WSL2, virtualized network components are created. So a different ip address is used inside of WSL2 versus Windows. You will need to create a firewall rule to allow traffic to pass between the 2 networks while running VcXsrv. TCP port 6000 has been referenced as needing inbound access.
New-NetFirewallRule -DisplayName "WSL" -Direction Inbound -InterfaceAlias "vEthernet (WSL)" -Action Allow -RemoteAddress "172.16.0.0/12"
Name : {acfd2235-385a-43a9-8a7b-820bcc5e2889}
DisplayName : WSL
Description :
DisplayGroup :
Group :
Enabled : True
Profile : Any
Platform : {}
Direction : Inbound
Action : Allow
EdgeTraversalPolicy : Block
LooseSourceMapping : False
LocalOnlyMapping : False
Owner :
PrimaryStatus : OK
Status : The rule was parsed successfully from the store. (65536)
EnforcementStatus : NotApplicable
PolicyStoreSource : PersistentStore
PolicyStoreSourceType : Local
https://stackoverflow.com/questions/61110603/how-to-set-up-working-x11-forwarding-on-wsl2