Rear struts are just* hydraulic rams afaik.
You should be able to reseal them for pennies if you are able to find a decent hydraulic seal supplier.
Many years ago I did a load of work on my dads 300te. One of the struts was leaking from a cracking in a weld at the top of the strut. I removed it,ground out the crack filled the strut with water and welded it up.
It lasted another decade until it was scrappaged.
I also referbed the height valve body and changed the spheres at other times.
It is supposed to used special merc only fluid from what I could tell at the time.
I got covered and stank for a week.
True story bro😀