Whey protein isolate. I am also lactose intolerant and while this is slightly more expensive than the most commonly sold whey protein concentrate it prevents the daily pants shitting that concentrate would cause, so it’s super worth the extra 5-10 bucks.

I usually buy pea protein from MyProtein online. I personally find whey proteins to be way too sweet. The only issue is that it’s thicker, so I need to use a blender, rather than one of those shaker cups.

Find a basic flavor like vanilla, and add fruit (usually banana for me.) You can add a non dairy milk of your choice, if you don’t want to use water. Soy milk works well, and has bonus protein.

I know you have been given answers already, but look for any Vegan protein. If you want protein powder for example, the vegan ones are usually made of pea protein rather than whey, completely eliminating the risk of shitting yourself from the protein.

Orgain vegan is my preferred protein. I like the simple one that is much harder to find

Whey protein is generally the best protein you can get (in terms of amino acid profile).

There are some good vegan powders but also some real shite ones that seem to have high protein but of low quality. One with a 70% pea protein and 30% brown rice protein blend is about the closest you can get to a whey powder. I’d be skeptical of one’s that don’t provide an amino acid profile table beside the nutrition facts. Good chance they’re inflating the total protein with poor quality sources.

Also, like someone else said, you can consider a whey protein isolate. If you aren’t avoiding dairy for ethical/diet reasons and just due to lactose intolerance, good chance you can have an isolate without blowing up your bowels.

Not sure if the whey powder itself has lactose, but most of them can be mixed with water instead of milk. It’s nowhere near as yummy though so maybe replacing with a milk alternative would be better.