Couple filing jointly, how much can each contribute maximum to 401k with different employers, if they earn, say $200K each per annum? $22,500 each or combined?

You can each contribute up to $22,500 in 2023 ($20,500 in 2022).

If permitted by the 401(k) plan, participants age 50 or over at the end of the calendar year can also make catch-up contributions. You may contribute additional elective salary deferrals of: $7,500 in 2023, $6,500 in 2022 for 401k plans.

IRS.gov