Assuming your wild yeast tolerates being dried, you can easily dry it and see how viable it ends up being. Save some of the wild yeast slurry in a jar and pour the rest in a thin layer on some baking parchment on a cookie sheet then leave that in the oven with the light on for gentle heat to dry. Make sure your oven doesn't go over 100°F with the light on otherwise you risk killing your yeast. You may need to put it on a rack furthest from the light to keep the temperature right. Store the resulting shards of dry yeast in a jar. Since it's wild, it will probably tolerate being stored in the freezer
To test the viability of it after drying, put a few flakes in a bit of warm wort in a jar you can seal tightly and let it rehydrate for 10-15 minutes. When it looks like it's broken up and rehydrated, shake the ever living heck out of it to aerate it well and let it sit. If all is well, you should see fermentation signs anywhere from two to 24 hours. Don't forget to loosen the lid to the jar to let the co2 pressure out.
If your wild yeast is anything like kveik, it could last for a decade in the freezer. Nothing to lose by giving it a shot! I plan on doing some wild harvesting this spring/summer and I hope I find something good too.