Yep, IR and BT are the standards on handheld meters, and they offer most of the same functionality as USB plus the isolation and inexpensive price.
As for resolution, really 3.5 digits and 5000ish counts will get you a pretty good read on most things, but as with many analytical tools, finer detail can show you more about your problem and help diagnose some extra stuff. Because it's easy to get a fair bit of resolution nowadays, I'd start at 5000 counts minimum and anything above is nice. It's probably easy to find 10-20,000 counts or more within your budget. That said, look for other features too, a multimeter can be really versatile and pack in a lot of features. I'd look for a high and low current range (usually means 3+ input jacks), a capacitance and resistance range, an AC voltage range with a true RMS converter, a diode check mode, a continuity mode, a relative measurement mode, a basic frequency counter - there are plenty of other options that are common, but those seem to come up most often for me. I'd look at some of Dave's videos on the subject, some of the multimeter reviews he does give you a good idea about common and useful features, and some of the shootouts, while somewhat dated, offer really good info of things to look for in a meter. Then there's tons of information in threads and spreadsheets here to compare and contrast models.
5.5 digit handhelds exist, I think, but are generally benchtop models (which, to be fair, are more likely to have an isolated USB interface).