Hello, I like to set up a vpn gate for ovpn(It must by ovpn no WG or something else). What is best hardware for this? I have 10' rack. It must be not expensive. I chose rb750gr3 its good option?

You missed and mention how many vpn connections you will be running at the same time.
And what speed are we talking about ? Do you need sfp or sfp+ ports.

And there are Mikrotiks Distributors that can provide these figures for you.
https://mikrotik.com/buy

For max 20 clients and I dont need sfp of sfp+

Possibly worth looking at and comments surrounding

viewtopic.php?p=1063801#p1063801

I like the hap ac2, though with current routeros versions you will likely need to disable and remove wifi packages.