It is not really all that complicated.

You can hold a commercial license without a valid instrument rating.....I have one.

I also have an ATPL with a lapsed instrument rating.

I can fly VFR with either license and be paid for my flying.

If you do not renew your IFR / medical, you will keep your ATPL until you apply to renew your aviation document booklet (ADB). I got this by an acquaintance at TC. They said that TC licencing will not reissue an ATPL if your IFR is not valid. If your IFR and medical are both expired, then they can't even re-issue a commercial licence. That is because each time you renew, it is treated as a new application for the licence and without a valid IFR / medical, you do not meet the conditions of issuance for the licence. I know a retiree who still instructs in the simulator but he no longer keeps his IFR and medical current. When he applied for a new ADB, he was given a PPL.