We still need rental properties, and small local landowners should be the priority.

Landlords aren't necessary for rentals to exist. We built hundreds of thousands of government owned properties every year(!) the UK's post-war period. Some of them have bad rep for looking like soviet blocks, but modern social flats look like any other now so that isn't a valid complaint anymore (I have to point them out to friends, they otherwise wouldn't have a clue). These can and have been very much used for temporary accommodation, like private rental units.

If you're more of a market economy fan: we also state-funded housing cooperatives, democratically owned housing. Vienna is the popular example where they even have shared communal swimming pools, but 20% of Norway's entire population lives in them and they're still growing steadily despite not having gov. funding for decades. It's not impossible to come up with a way to use these as rental units while retaining the democratic element (i.e. the renters "own" the flat while they rent it and "sell" it on when they move). In Norway, for example, you're exempt from property transfer taxes when you sell a coop flat meaning there's no tax friction if you want to move from one coop flat to another. Since the flat is never technically yours in a coop (only the share giving you the right to reside there) it just goes back to the coop when you move out, and they can handle renting it on to someone else (so you don't need a slow bartering process to move out). Your rent can also straight up go towards a larger share in the property, so you're not propping up some landlord, the only thing you're really paying for is management of the coop like you would with a privately owned block of flats anyway (except the coop probably wouldn't spend thousand on an Xmas tree).

If we're going to be thinking about government regulation and law changes anyway, we may as well try more than just small ""ethical"" landlords. They may well be part of it in some limited way but let's think beyond just that.