I had a 10 year old APS Sony A77 dslr(dslt) 24mp that did have in body stabilization and it was quite effective. I believe Minolta/Sony were the only ones to offer DSLR's with in body image stabilization (probably a pattent thing). My A77 was stolen last year and my home owners insurance paid "replacement value" which was enough to allow me to buy a mirrorless Sony A7RIV (61mp). The A7RIV is a GREAT camera BUT in a lot of ways I REALLY miss my old A77. Just having 10 years of familiarity with my A77 is going to take a long time to replace as getting to know the nuances of the A7RIV is quite an uphill battle. If my A77 was not stolen I would still be perfectly happy shooting with it. Since I had the opportunity to buy all new gear buying a mirrorless camera made a lot more sense to me than buying a DSLR. If I were you I wouldn't be too eager to upgrade to mirrorless. After all the hype the actual results from upgrading aren't that near the "huge leap" as they would like you to believe it is.
When I bought my Sony A7RIV is was with the intention that I would get a minimum of a decades use out of it. Having used it for a year now I am very comfortable that at least a decade won't be a problem. (I probably could have squeezed a second decade out of my old A77 though).