Is two x16 slots a concern.
Are more required immediately.
I'm trying to avoid bios flash update on Non Ryzen 3l board.
They don't need to be 4.0 or wired for x16. It is rare to see slots other than x1 or x16.
Some cards come only as small as x2 for now.
Eg:
1. GPU x16
2. 10GbE x4
3. USB 3.1 x2 (for front panel)
The cheapest X570 board with 2.5GbE costs 330 euro
The cheapest X570 board with front panel USB 3.1 costs 207 euro (it has two x16).
Beware that a card might be x2 3.0 but the slot x16 2.0, so you would need an x4 2.0 card instead.
Before buying a board you need not only check the wiring of the slots but also the modes of operation when you plug other things.