Linux System Admin - TTFB Issue

Looking for someone to help us check our server, database and site due to getting a much higher TTFB after moving to a more powerful server. Other sites identical to our main site that just use different domain extensions (.uk, .ca, etc..) all have a much better TTFB. Sites run on Wordpress with NItroPack, Litespeed, cPanel, AlmaLinux 9.

Please only bid if you are the one who will work on this and have extensive experience in these kind of issues. Please also only bid if you actually read this.