Don't forget about hm1k. There are versions with classic r2r chips, as well as Himalaya version. I have the latter and find it enjoyable. Not true r2r sound like my hm603s with Phillips tda. But still good. Better than ru6 and fc6 dongles I've moved on from.
Aliexpress has many enjoyable r2r portables , like w510 and l1387 portable. Using proper Phillips chips.
Himalaya and modern r2r imitations through fpga (cayin, fiio, hiby etc) are interesting solutions, but lack some core r2r attributes. Technicalities are improved, while trading off some analog timbre magic.
Listening to hm1k Himalaya with ex800st right now, very enjoyable no lie. Very creamy and inviting musicality.