If you’re carrying multiple bikes, and the weight is starting to add up, it’s completely normal to have some trepidation about stability. But thankfully, there is one option that is as solid as your frame.
Getting a hitch-mounted bike rack is the best solution in this case. And they have the most variety of choices for holding multiple bikes. So if you have a growing family, or you just like the idea better of something that’s “locked in”, then this is probably the choice for you.
As for installation, your local uhaul can install a hitch for you. Or if you’re handy, you can buy the hardware yourself.