I doubt its as simple as the purge valve. The vent valve would almost certainly be involved as well. But that’s why DIY is probably not a great idea. Guessing at parts that need to be replaced quickly gets expensive.
It is also the case that evap system issues are notoriously hard to track down. So in the long run you’re probably better off having someone who does know about cars track down the exact issue. This itself can, of course, be very dicey since it can be hard to find someone competent enough to do it.