Hmmmm. Maybe not what you want to hear but...
Personally I can't understand moving from a tool designed for the job to one that isn't.
Wordpress is a blog platform.
Woocommerce is a big plugin to force it to do something it wasn't really designed to do. And probably needs plugins for the plugins....
Plenty of pages out there on topics like
"woocommerce slow admin ticket"
Various suggestion on disabling loading unnecessary scripts etc. That's probably your direction of travel to start with, all other things being equal. Check with Chromium/e dev tools to see what takes time.
Yes, possibly have a look later at mysql/php optimisations (PLEASE share things you find to the wiki or a bug) but my guess is you need to look at the core code.
Having used Zencart for years I don't dispute it is long in the tooth and I have sites running other packages too now.
Personally I'd look for a proper ecommerce/ticket platform designed for the job. It should offer much better performance. Might cost you a bit more short term but save you chasing ghosts...
IMHO of course......