- "The monitor you used to test the game here at itch, is it 60hz?"
Yes, my monitor is 60hz. As far as I am able to tell, 60hz is the general industry standard for computer monitors. While many high-end gaming hobbyists have a fondness for the fidelity of 75hz, 120hz, and 144hz monitors, the vast majority of software users and game players use monitors or TVs with a refresh rate of 60hz, which has been the NTSC industry standard for decades.
For context: the 60hz standard existed before video games or home computers; it was originally the American standard for AC (alternating current) electric grid frequency. CRT monitors used this as their refresh rate because it was easy to synchronize.
- "Anyway, maybe the V-sync is still in the executable. Would working with max frame 0 (unlimited) be a bad practice?"
If the game's coding is going to be mostly or entirely Frame-based, it is probably a bad practice to export with an unlimited max frame rate. If the game's coding is going to be mostly or entirely Time-based, it will matter a lot less.
With Frame-based coding, non-standard refresh rate users are always going to experience problems until they set their monitors to 60hz, but I personally think limiting the frame rate is the correct course of action in this scenario. If the frame rate is unlimited, this can result in insanely high speeds (a game designed for 60fps running at 144fps, for example). If the frame rate is limited, this will result in slowdown, with one exception: 120hz monitors will experience a perfect 60fps. While this is probably a matter of preference, I think a bit of slowdown is preferable to a theoretically large speed-up.
There are no great solutions to this problem. I think a lot of this comes from mismanaged hype on the part of manufacturers of high-end computer monitors. Additionally, this is mostly a result of GDevelop's "Web-First" design philosophy, and while I would personally like it if there was native support for disabling VSync in desktop distributions, I do not currently expect them to devote resources to that, especially while they're still developing the experimental 3D engine.