I'm still using a Logitech M325 that I bought maybe 10 years ago. It has a smooth scroll wheel. I bought a bunch when they were on sale at Best Buy, thinking that it was a good price (maybe $10?) and I'd just replace them as they failed. Or (I kid you not) my kid did something weird with one. This one has had been cleaned, disassebled, dropped, repaired, etc. But I like it so much that I continue to use it. It's a pattern that was discontinued a while ago but I like. I suppose I could try and find the exact one on Amazon or eBay, but why? This also has the Unifying receiver, so if it's lost or stops working I have a few spares that could go in its place. I wouldn't pay $20 (about what Logitech charges) for a receiver though.
And they're still being made. But you need to look carefully because there are different models that are similar. The M325c should be mechanically identical but will have a "designer" graphic of some kind. I have a spare M317 that has a "bumpy" scroll wheel where you can feel it when scrolling.
Here's the M325 sold directly by Walmart:
https://www.walmart.com/c/kp/logitech-m325-mouse?facet=retailer_type:Walmart
There are other places that sell it, although the office stores like Stapes or Office Depot might to have it for a sale price.