No it won't.
> "it’ll help you accept payments"
No it won't.
> "or sign up for a bank account"
No it won't.
An LLC doesn't make those things any easier than they already are (very easy) as a sole proprietor.
An LLC only does the liability thing. And that's fine. Just don't make other things up. You don't need to.
No it doesn't. Sole proprietors get EINs just fine. It's literally the first option on the first page of the application. https://sa.www4.irs.gov/applyein/legalStructure
> "and DUNS number"
No it doesn't. Sole proprietors can get DUNS numbers just fine. It's literally the first option when you tell them how your business is structured right after telling them your name and email address.
> "Yes it absolutely helps with accepting payments"
A billion people accepting payments in every possible form without being incorporated say that you're wrong. No method of payment processing, from credit cards to memecoins, cares whether you're incorporated.
> "having an EIN is necessary in many cases"
Again, getting an EIN and forming an LLC are completely unrelated.
Credit card? No. ACH? No. Wire transfer? No. Cash? No. Crypto? No. Check? No. IOU on a napkin? No. Pokemon card? No. Sex? Weirdly illegal in most places, but still no.
...uh...which ones did I miss?
Yes, you can go get a personal loan, or a retail banking account, or a personal payment processing account, but as I said, you're going to be locked out of a lot of B2B products.
Example, since you edited to add examples: I have several business bank accounts and far too many Stripe accounts all registered as sole prop. I haven't had to take a loan but I do have a sole prop credit card. My understanding is that even with an LLC a bank is going to require a personal guarantee for a loan.
What it does do is that since it provides a rigid structure, it compels law abiding citizens to do those actions, not forcing still.
You would have a hard time proving liability if you didn't have separated finances.
Also, you should separate finances as a sole proprietor too.
An LLC will require you, under civil or criminal penalty for non-compliance, to separate personal and work finances.