My highlander has been reliable but the maintenance can get speedy. Start/stop engine batteries are more expensive. I have the V6 and the intake manifold has to come off to access the back three spark plugs during the service interval at 80K. I’ve also needed 3 alignments in ~100k miles.
I was able to bypass the Start/stop engine battery on my Jeep Wrangler and removed it.
Youtube showed me everything I needed to know about how to do that.....maybe you can do the same.