My first choice would be playground=youth_bench. However, in addition to the 323 entries of this type, there are also 4 instances of bench:type=youth_bench…
on taginfo, and thought that could still be erroneous use, with those numbers.
I guess tbere isn’t any other tagging to show that multiple people can sit there, behind each other?
They’re almost a very small type of leisure=bleachers. But in that case they’re also not usable as such, no backrest, and no “ground” to walk on in-between the beams.
I would be fine with tagging the three two-beam benches as playground=yourh_bench, but the three-beam ones look even less like the examples on the wiki.
Also; the bottom beam(s) is not a dedicated footrest, it’s firstly a seating surface – all of the ones on the wiki show smaller, lower and dedicated footrests.
Why should bench:type=youth_bench (think of Any Tags you like!) erroneous? Sometimes it needs time before a tag will be established - and such a type of a bench will not come along so often…
I suppose bench:type=block is reasonable. If these are just big blocks of wood, then playground=youth_bench doesn’t seem appropriate, they’re not cool enough. And their configuration would seem to be wrong - playground=youth_bench would seem to have a configuration that would allow someone to ‘spring’ off them.