I looked around for a bit and found this as a possible solution, much like what you guys described, which was to use DNS auth.
Following that exact solution I managed to get it working. I'll leave here the command I used for acme acme.sh to generate the certificates for future reference.
./acme.sh --issue --dns dns_linode_v4 --dnssleep 900 -d 'lan.henryrocha.xyz' -d '*.lan.henryrocha.xyz'
Obs: This command is explained here.
Thank you!