TRIAC on a Secondary, RC snubber, and other protections

[Feliciano]

I have a Chinese single-side through-hole power control board made with Chinese generic parts. It's a thermostat-like controller.

Some other people has reported several blowns of the board and/or the load. I think it's related with possible several hundred Volts spikes/transients due its lack of protection and bad manipulation (remove the load when live). To prevent that ever happens to me, I want to improve the circuit by adding some protections. In my country, forget about parts from the 21st (not even a MOV), so I'm working a solution with just few discrete traditional components.

I add a simplified schematic of the critical subcircuit, with some modeling of somebody connecting and disconnecting the load live, or having attached a SMPS module to it.

Is there a more effective way to achieve/improve this protection with low-tech parts?