I have to get a lawyer there anyways and talk about the implication of him doing this without notifying me and redo the loan paperwork .

Also, staging and professional photography can help potential buyers visualize the space better.Lastly, think about local advertising—social media, networking, and maybe hosting an event for local agents could help get more eyes on the property.

I do occasionally post about it on some of the social media sites for travel nurses, such as Travel Nurse Gypsy Housing for example. 

We used to use them for direct mail, email, and social media ad campaigns. 

I believe the sponsor still is on social media going about their day to day

Most serious and qualified tenants are searching on the major 3rd party platforms you mentioned + realtor.com, redfin, and a few others.Apartments.com & homes.com are owned by the same company and may offer some additional marketing options.Another strategy to consider here is social media - video marketing.

Look up Devana Came on socials.

Look up Barbara Isabel on socials in LA.

This is not myface or spacebook or any of those awful social media outlets where people are a**holes to each other.   

It is NOT like what social media or influencers try to paint, it's hard work.