New vent or no vent

I am installing a new toilet that will be about 6-7 feet away from the main drain stack.
I will use 3" or 4" to connect to current 4" waste line.
Will I need to install a vent on the drain line to the waste line?
Can I connect to any vent that is close to the run to the waste line? T-into toilet waste line to connect to vent in waste stack.
Should I consider using one of those valves in the wall(can't remember name).

Thanks
John

Here's part of your question answered. The "valve in the wall" is an air admittance valve, aka Studor vent. Whatever you call it, it can not be hidden in a wall. If they are permitted in you area, and they are not OK everywhere, they must be located where they can be replaced in event of failure. I'll leave the rest if the question to the pros as these are not all just yes/no answers.

A toilet should be vented within six feet.
Depending on your local code, it may be with a 2" line, or larger.

It can tie back into other vents above the flood level of the combined fixtures.