gianniscfa

Yes, SOME boards work with Zen +, not all of them. Bunch of B550 chipsets supports only Ryzen 3xxx, 5000x series cpus.
But he should consider that his ram MIGHT NOT work on 3200MT/s, but rather 2933.....cause that is what Ryzen 5 2600 supports.
B450 chipset should be cool.
He can try Gigabyte, MSI....there are affordable boards....60-70 $/€.

Yeah, don't run Valley.
 
Better off running Superposition or 3DMark:
 

If you want to OC, you'll need to change the CPU cooler for an AIO water cooler or a better air cooler. 
 
Good choice for the MSI motherboard. 

This would be a good choice for your budget:
 
PCPartPicker Part List
CPU: AMD Ryzen 5 2600 3.4 GHz 6-Core Processor  (€147.09 @ Amazon France) 
Motherboard: MSI B450 TOMAHAWK MAX ATX AM4 Motherboard  (€124.90 @ Amazon France) 
Memory: Corsair Vengeance LPX 16 GB (2 x 8 GB) DDR4-3000 Memory  (€79.98 @ Amazon France) 
Total: €351.97
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2020-04-09 15:57 CEST+0200

then i will stick at the 2600 . 
i am sure i will differences with my old i5 6500..

AMD has made PC building a lot more interesting

You're in CPU upgrade territory with that budget
PCPartPicker Part List Type Item Price CPU AMD Ryzen 5 1600 (12nm) 3.2 GHz 6-Core Processor $85.00 @ Amazon Motherboard ASRock B450M PRO4 Micro ATX AM4 Motherboard $79.97 @ Amazon Memory G.Skill Aegis 16 GB (2 x 8 GB) DDR4-3200 Memory $64.99 @ Newegg   Prices include shipping, taxes, rebates, and discounts     Total $229.96   Generated by PCPartPicker 2020-04-08 17:09 EDT-0400   Sell your CPU and ram and you've got quite the new system on your hands

1920x1080 is the usual realm of good performance but 2560x1080 is not much more demanding.