SunJoe is kinda an odd bird, uses I think 14mm fittings where US are 15mm (or vice-versa):
https://www.mtmhydroparts.com/products/14mm-plug-x-15mm-plug-conversion-adaptor
Have had (2) Amazon cannons (MATCC and DUSICHIN) and they worked `OK`...most of the time.
Much prefer the (albeit more expensive) MTM cannon. If foaming a car becomes an inconvenience, I`d likely quit doing it so for me, the heavier duty MTM stuff is worth it.
To get decent foam with the Amazon guns had to crank all the way to the stops (given the product dilution I was using) and with the PF22 I get better foam at same product dilution with room left on adjuster dial. Adjustable orientation nozzle is nice as well
Not sure yet whether I prefer the stock PF22 bottle or one of the other `straighter` bottles yet but the stock PF22 bottle does stand on a flat surface a bit easier without tipping over. The threads on the neck of the hourglass bottle may seem just slightly more prone to cross-threading but really a non-issue if, you know, you actually pay attention to what you`re doing...sometimes I`m a bit weak in that area!
As an aside, from a pure hobbyist standpoint, make sure your pressure washer/foam cannon setup is easy and convenient to use...otherwise you`ll quickly tire of the routine if it becomes a time consuming and inconvenient. Swivels, quick connects, hose reels, water `manifolds` for hose bibs, etc; if it`s not quick and easy to use, it`ll likely end up like exercise equipment...un-used aside from a clothes hanger/storage rack.
You may be able to put together individually but the spray gun/cannon kit is a nice kit that includes everything to get ya set up; the small MTM SGM35 spray gun is much easier to use as well. And you`ll save yourself a bit of time and aggravation chasing pieces down although you could likely save $20 or so doing it, I`m too lazy and just snatched up the kit: Link Removed
It`s a good setup, just wish I wouldn`t have had to go thru the cheap stuff to find the value of the MTM pieces.
FWIW I`m using with a Sunjoe SPX3001, 2030psi, 1.76gpm electric pressure washer; MTM stuff works great with it.