It's not stupid question at all.
First of all for acrylic tubing there is no easy way, at least not at home. Laser cutter is nice... but hardly viable option.
PETG is different animal entirely. Look no further than couple post above your question. There is no need for heated wire cutter. It may rupture PETG structure if too much heat is applied and tube will just look like burned inside.
Get composite tube cutter. You will get extremely clean cuts (except when you need to cut like 0.5 cm then it get dicey). My recent major refit took me less than a week to go through entire overhaul of tubing from classic ZMT to PETG and I was doing that first time in my life. With hack-saw it would be probably a month of work - tried it few test times, what a mess with no tangible gains. And then I had to accommodate sas expander into the loop. With flushing, bending, measuring, redoing 3 segments of the loop and stuff + filling the system back I was done inside one day and half of work. No sanding, hacking, white powder mess, splinters. Just measure, cut, bend, screw fitting, repeat. Plan is the most important.
Right now in my loop there is exactly 20 HDC 16/12 EK fittings (counted twice
). I had only 1 oring causality at the beginning when I was trying to force the issue when fitting was dry. My beginner error.
Granted. When edges of the tube are sanded, tube slide in very easily, but IMHO to easily sometimes. I will take one or two damaged fittings and solid contact by tubing inside the fitting than no casualties, easy slide and potential leakage point any day of the week.