Sounds like a good idea. Your trap is probably missing or deficient.
If you had a working regular trap, you could stick a cotton cord or rope in there to the bottom, and find about 1.5 inches of wet due to water standing in the trap.
Some traps have a cleanout plug on one side of the bowl. Could yours be missing the plug?
I picked up this drain! https://www.amazon.ca/Liquid-Breaker-GD102-Green-Drain/dp/B00W2FPBJG/ref=sr_1_2?crid=26S85PY9BXJPA&keywords=drain+trap+seal&qid=1590503581&sprefix=drain+trap+sea,aps,145&sr=8-2 hopefully it all works out. I got the 4 inch one after measuring the drain. Thanks so much for your help.