Check for the easy fixes first. Sounds like you did the usual resets. I would make sure the charger is good or try another one. I might also see if you can get it into DFU mode, and revive/restore if you have access to another Mac.
After that open it up and have a look. They do require a pentalobe style screwdriver bit, but that aside these open very easily. Look and see if anything is visually off. If nothing is obvious see below.
A few places I would check:
1. The battery, unplug it and see if you get power on just the charger alone. The fan will likely rev to full speed since the board is expecting data from sensors in the battery and in their absence it will go into a protection mode, assuming the battery is extremely hot when the sensor data is missing. So this is expected behavior when the battery is not plugged in. But a faulty battery can definitely prevent power on.
2. Check the USB C board. You can usually wiggle it out without removing any additional components. See if there is any corrosion on the pins, or any pins that are smashed together, missing, etc... where the charger plugs on. I have seen this a LOT especially with these Retina Airs. No liquid damage anywhere on the interior, but corrosion in the port.
3. The Audio board. These are prone to liquid damage and a small amount of damage to certain components can be all that is preventing the unit from powering on. Unplug it from the logic board and see if you get power. This will likely also make the fan run at full speed, for similar reasons.
4. The trackpad. Same reasons as the audio board. It's a place where water can easily creep in and murder some components. Unplug it from the board and see if you get power.
Any of these are an easy fix (aside from trackpad, it's easy, but getting it out is a bit of a pain on the 2018-19 Airs since you have to remove the logic board to get to the keyboard bit of the combined flex cable). If still no love after checking these, your issue is likely the actual board. In which case you can see if you might find someone who can repair boards to have a look. Unless it's just liquid damage everywhere, in which case a swap would likely be a better option.