Switching to a personal router

[Andy70g]

Hello everybody...
Well, I think this topic is not exactly new but, anyway, it'd be great to get some advice from you.
My VM Hub 3 is misbehaving two-three weeks now: duplicated IP address messages (it makes no sense as the DHCP server is up and running), error messages regarding port-forwarding settings I've been using almost five years now.
As I can't get the newest VM Hub 5, I was thinking to put my old faulty and buggy one into modem-mode and attach a brand new router to it.
Just a few questions: will the speed be always the same or do I have to expect a decrease?
Will I be able to use all the advanced features on the new router, like port-forwarding, IP address reservation and so on?
Thanks a lot...

[legacy1]

You get the same speed as you do now unless you do QoS/BWM on your new router you may get better wifi speed and longer range all 3rd party routers do port-forwarding IP address reservation but you can check before you buy then put hub in modem mode.

Some thing like this is good

https://www.amazon.co.uk/ASUS-RT-AC65P-Dual-Band-Gigabit-Repeater/dp/B07NW64C4M/ref=sr_1_25?crid=1C6...

or go better