I have used this type for years.
https://www.bunnings.com.au/silvan-16l-rechargeable-backpack-sprayer_p2970560
The wand got swapped out for a brass one that has a very fine mist nozzle on the end, but the stock ones work just fine.
The problem with ANY of these units it leaving material in them.
Lots of sprays are suspension concentrates, when you let them sit they build up on surfaces inside and block them.
Pesticides are specifically designed to
attach and stay there
So if you leave spay in your tanks and wonder why it doesn't work a month later then that's why, yes you can wreck them in a month.
Even the crap ones will be fine, just rinse them out and run warm water through them after use.
Read the label/msds if it has SC then make sure you rinse. Things like pyrethrin can be left in the tank.
Edit, this is the first Lithium type I have used, the previous ones were all sealed lead acid, this new one has gone 9 months so far no problems.
I wish they didn't change them from lead batteries they were just fine.
My problem is the tanks get brittle from uv after around 5 years and they crack when banged around in the tray.
If you want to change the wand/trigger/nozzle to brass it will cost that much again just for that, but it's a one off purchase that will last a lifetime.
I got mine from Agserv in port melb.
Each time you get a new sprayer just swap the wand over.