I have replaced the inner tubes several times. At 3 bar they will burst after a while. Even at 2 Bar they may burst on a hot day if inflated on a cold day. The best solution I have seen so far: foam filled tires. Foam filled tires are as hard as a 3 Bar inflated tube but never bursts. and a hard tire is much easier to pull. By the way, my rims have deformed due to the sun’s heat. This is may be another reason the inner tube burst. I can imagine the tire being pushed off the deformed rim by the too high pressure. (Not sure though, I wasn’t there when it burst).
Trolley wheels are exactly the same as wheelbarrow wheels. Foam filled wheels should be available from any builders or farmers supply store. You cannot put a foam filled tire on your existing rim, you have to buy a complete wheel. (AFAIK the tire is filled with foam after it is put on the rim. similar to how we put air in a tire). Some wheelbarrow wheels have ball bearings, replace those by the reducers of your current wheels but others have reducers instead of ball bearings. Check this when you buy them. Just 2B sure, bring an old wheel to the store to compare.
On the other hand, a foam filled wheel would set me back 17 Euro’s whereas a new inner tube costs only 1 Euro, go figure….