Will a new vent resolve pressure evacuation of my drain traps?
Did you replace your pipe and keep the 2% slope?  I think your fix will work.  Assume your main stack is 4&quot; and your toilets are on 3?  You might be over the critical trap arm length for the basement toilet but that would just siphon that toilet.
Even if this wasn't a problem you need a vent for your main stack and it needs to go through the roof.  You don't want the potential for sewer gasses to build up and vent into your house.
Good explanation of the critical trap length.
https://www.jlconline.com/how-to/plumbing/maximum-length-for-fixture-drains_o