Yes and No... According to abstinence studies after 7 days without ejaculation there's a big spike in Testosterone levels, but it goes back down the next day. After 3 weeks without ejaculation, T levels are slightly higher than baseline on the chart, and didn't reduce as much from Fapping, I don't know about DHT though. From Anedoctal claims online people have reported improvement with their hair, but after a few months or so, I've read people claiming that they start losing ground again.
So, I personally believe that long term abstinence will hurt you in the end. Your body won't stop making T, and sex drive is not the only thing your body uses T for. If your deprive it of orgasm and sexual thoughts long enough, eventually your body will probably use your T in other ways.
Look up pics of the Dali llama, He's supposed to be Abstinent. (I guess it's possible that he's Jacking it secretly, but that is hard to imagine to be true)
Sometimes his buzz cut is short enough to see his hairline is not complete. I also think too much abstinence increases sensitivity.
Now with that said, After orgasm, Prolactin levels are elevated for about an hour. There are Prolactin receptors in scalp, and prolactin induces Catagen phase. I don't know, if the one hour above baseline has much effect but I imagine Jacking off Everyday, would. then that would be higher than baseline prolactin for an hour everyday. However, Masturbation is not the Same as Sex, the prolactin release is correlated with the quality of the orgasm, and after sex there is 4x the level than after Masturbation.
Here's the thing prolactin is both good and bad in some ways, Prolactin causes catagen,that's bad, But it also reduces T and DHT and T/DHT also cause catagen/aptosis. A number of experimental data indicate that hyperprolactinemia inhibits the activity of 5-alpha-reductase. Prolactin also inhibits GnRH which reduces the release of Lutenizing hormone, ( LH increases T production) BUT I have read that it upregulates Lutenizing Receptors in Leydig Cells( cells in testis that make T) So, it could increase LH but increase sensitivity to LH,, and may decrease T short ter but increase it long term...
Also, I could see abstinence from pornagraphy being beneficial maybe. And I think the way you masturbate matters to. If you are spending Hours searching p**rn looking for that perfect video, increasing your Testosterone and then having an orgasm not as powerful as sex or powerful enough prolactin release to counteract that T inducing p**rn viewing. (There may be some conflictng information on if p**rn viewing increases T, I read one study somewhere that said serum T levels rose 90 minutes after p**rn viewing Without fapping)
Here's some links with links to studies on abstinence and T levels and such.
https://www.anabolicmen.com/ejaculation-testosterone/
https://www.yourbrainonporn.com/book/export/html/148