Lucky for me I took the check pilot path quite early in my career.
So when ‘retirement’ came I already held all the TRE/IRE and simulator approvals needed to work part time.
I have not missed flying - in fact prefer the stability and mental stimulation of sim work without all the hassles of customs, security, packing and unpacking each night in a different hotel, early wake up calls to repeat the security, customs etc bull!!!! all over again next day, arriving home too buggered to do anything physical etc.
I sleep better, have more time for leisure pursuits and believe my health has actually improved since quitting flying.
Occasionally I still do get in the pilot seat but only for fun now, and on my terms.
There are other avenues, particularly if you can write well. Manuals, training programs etc. Or lecturing theory subjects, though that does not pay much. The trick is not to take on too much. Learn to say “no” to some of the demands that will come your way. Even if you can afford to work for nothing, insist on a fair day’s pay. Do not undervalue your experience.