Check if "--preferred-chain "ISRG Root X1"" is active?

Well, you may have traded joy for one group of people for sadness of others.

Using the "short chain" will prevent older Android devices from connecting safely. See more about that here

But, to answer your question, you can see the chain your server sends with a site like below. If it ends in ISRG Root X1 (2 certs) it is the short chain, if in DST Root CA X3 (3 certs) it is the long chain.