Worth upgrading fork on entry level bike or save up for higher end model?

Hello!

I bought a Liv Tempt 3 in 2020 for CAD $699, which I believe is an entry level mountain bike, and have since put maybe 1500km or more on it, mostly on road with the occasional trail run.

I sent it to the shop around 2 years ago for a general tune up and when I got it back, the fork wouldn't lock anymore. I took it on my first proper mountain biking trip yesterday and I thought the fork was stiffer than I would have liked + I may enjoy more than the current 100mm of travel.

Naturally, I went to the shop again to ask for advice on repairing, upgrading or getting a new bike entirely and they said they would need to ship the parts to another location for diagnosis and then determine if maintenance would be required. However, if I choose to go with the upgrade route, they say a new fork would likely cost me upwards of CAD $600, which is almost the price of the whole bike.

I've been looking at the Suntour upgrade program, which offers a $100 rebate on new forks when a proof of purchase and serial number of an existing lower-end fork is provided. This is an interesting option and would leave me with the following choices, given the straight steerer tube on the Liv Tempt 3

• Raidon
• Epixon

I've read that simply changing a coil fork for an air one (i.e. either of the above) should already feel like a massive upgrade?

Any thoughts on the matter? Is it worth trying to improve on my SR Suntour XCT30 HLO fork?