If the current 4Runner still uses the 5AT it should have a transmission dip stick. Or any manual. I think some heavy duty trucks still have them too. It’s really only a limited amount of either vehicles carrying old power trains or special duty applications. ZFs are out of the picture so no point in looking at FCA/Stellantis cars or any European brands.
A lot of these fluids are lifetime because the transmissions itself will go out before the fluid will. Check Nissan and Subaru CVTs. Even some of the ZF transmissions will have pan gasket leaks before 100k that will require changing ATF anyways. I wouldn’t lose sleep on a car that didn’t have a ATF dip stick. Most likely ATF won’t be the issue.