For a 4th gen, any version that's at least a couple years old will be fine.
I don't think any of you guys are doing reflashes or using any of the more dealer/manufacturer specific stuff that we'd use (mainly because a lot of it is centered around data recording and collection for sending to Toyota). The vehicle is old enough that they aren't adding anything to new versions of the software that would really affect anything you do on them.
As for dongles/OBDII boxes, I'm not sure what is out there these days. The majority of the cheap ones used to come with old knick-off Gen1 Mongoose VCI cables; not sure what they use now to be honest. Anything Chinese/Knock-off I would highly recommend either running in a VM and/or scrubbing religiously before using, they are known to have plenty of malware in them.
Edit- If you're just looking for a more capable OBDII reader for your vehicle you could look at companies like Autel who sell a variety of tools at various price points and capabilities.