pi4b case/cooling recommendation?

A very popular choice is the Flirc case - I don't have any personal experience with it but other team members are quite happy with it.

Flirc Raspberry Pi 4 Case - Flirc

best Cases from flirctv - Flirc

flirc.tv

Personally I use this "Armor case", as it still lets me access the GPIOs and one can plug in a HAT (eg audio card) with a GPIO "stack" header

Raspberry Pi 4 Aluminum Alloy Heatsink Armor Case

This is an armor aluminum alloy case designed for the Raspberry Pi 4 computer model b by Geekworm. This armor case is only fit to raspberry pi 4 model b;

geekworm.com

There's also a variant which fully covers the RPi and GPIOs:

Geekworm Raspberry Pi 4 Heavy-duty Aluminum Passive Cooling Metal Case (P173)

This Raspberry Pi 4 Aluminum Case Pi 4B Heat Dissipation passve cooling metal case housing is specially designed for the latest Raspberry Pi 4 Model B…

geekworm.com

I also have the latter case but it seems - like with most cases that fully cover the RPi HDMI connectors - that you might not be able to fully insert the HDMI cable if the case or the HDMI connector is just 0.2-0.5mm too wide/thick.

so long,

Hias

I have several Armor cases and have put on a 50 mm 12V fan connected to 5V GPIO, cant hear it but my overclocked Pi4's never gets over 40C.

I am using the "Geekworm Raspberry Pi 4 Heavy-duty Aluminum Passive Cooling Metal Case" linked above. It works great, but WiFi does not work well due to the antenna being surrounded by metal.

But I love it because it keeps the RPi4 cool (currently 42.2c) without a fan and it looks nice on the desk.

Stay with the passive approach, and use external WiFi. You will have no driver issues with this, because it uses the Ethernet plug:

https://www.amazon.com/dp/B07Z1SGWL5