My suggestions.
Most software products provide some listing of recommended hardware requirements in the form of "minimal", "recommended", and 'best".
You do not want minimal and you do want as much best as you can afford.
Compare your hardware selections with the hardware requirements of the OS, applications, and games that you have in mind.
Hopefully the hardware you have in mind will be "recommended" or "best". And within your budget.
Do not skimp on the PSU. Critical component.
My overall recommendation is that before you purchase any component that you read the applicable User Guide/Manual for the MSI B550M Motherboard that you have chosen. Ensure that the motherboard does indeed support all of the other components being considered. Visit MSI's website for more information and updates.
Likewise read the applicable User Guides/Manuals for all other components and again visit the manufacturer's websites.
Pay attention to all fine print and warnings. Check manufacturer's FAQs and Forums. Pay attention to both what is said and what is "not said".
First builds are quite challenging and you must be willing to take your time, read, learn, and plan out each step in detail. Beforehand.
Do not make any guesses or assumptions. Go slow, step by step. Clean orderly work space. Proper tools. Well lit. Do not work tired or otherwise in some hurry up manner.
Read everything. Double check everything. Make notes to yourself. Especially if some instruction, diagram, photograph is not clear. Find the answer before proceeding.
If you discover something that is not clear or otherwise seems astray or even wrong. Post accordingly. Do not go online and do whatever some YouTube video may suggest.
You do not want your first build to include sparks, smoke, and odors.