A difficult question for me to answer as I am not involved personally with visas and extensions. If you do not renew the passport this year, then you will get a 10 month extension until 27 October 2022 and no doubt a further year from that date in your new passport.
You will be aware that a passport needs 6 months validity to be able to travel to most countries, although that is unlikely to affect you.
If you are happy to get a 10 month extension for the price of 12 months then wait, but I would recommend applying for a new passport at least 6 months before October 2022, and make the application immediately following a 90 day report. If you want a full year extension, then apply for a new passport ideally in May/June this year and immediately following your 90 day report.
HMPO have recently advised that new passports are taking up to 8 weeks to produce, and with the wait time to obtain an appointment with VFS Bangkok, timing is critical. It could get better though it could of course get worse