Lagering in keg

I plan to brew another Helles and want to try my hand at re-pitching W-34/70 dry lager yeast in a back to back brew. My lager freezer will only hold one fermenter so I thought I would leave the batch in it now for 3 weeks in the primary and cold crash it and rack it into a corny and lager that in my kegger to free up my freezer for the new batch with the re-pitched yeast. There is a lot of trub in the primary now so I wonder if I should rinse it or just re-pitch it as is. Any advice on these two questions? Thanks

If you are sure the fermentation is done on the first beer, you can cold crash in the primary, then rack the cold crashed beer to the keg and lager it. If you have another keg, you may consider racking it to a clean, CO2-purged keg after the lagering period, just so any other particulate is left behind and you get clean pours. I haven’t had great luck with conditioning beers in the serving vessel, as I seem to get some sediment with each pour if I go that way.

On the yeast rinsing question, I would try to do a rinse separate out some of the trub. Just make sure everything is really well cleaned and sanitized, and do another starter with the rinsed yeast just to get them active (especially after cold-crashing)

Maybe I should rack into a carboy and lager in the kegger in that?

I routinely lager (and fine) in the keg. I’ll usually leave my helles in the primary for 5 or 6 weeks, cold crash and keg w/ gelatin added in the keg. I just re-pitched dregs for the second time into a pre-pro last weekend- super start up.