Thanks for the recommendation, but I do want a case to work with as well.
Seconded the above. The CM NR200 is a very good affordable mini ITX. It's not the smallest so it's relatively easy to build in and has plenty of airflow for your system. You can use stock cooler if you're not running a toasty cpu + one extra exhaust fan at the top. I have NCase M1 but if I could turn back time probably I'd wait and choose the cheaper NR200 instead. For the board, I recently bought ASRock B550 Phantom Gaming ITX from Amazon SG for around $275. Quite a good deal I'd say.