Any experience with JAL and / or Sri Lankan when trying to transit on separate tickets?

I am thinking of flying JL39 to DEL (4:00p arrival), then connecting to UL169 (6:45p dep) as separate tickets & PNRs.

2h45m should be fine if JL denies the request, and I need to clear customs. Hopefully, even in that case, they still check any bags through.

(The other way, UL195’s 5:45p arr to JL30 @ 7:05p is tight, so looking at a 4:15a arrival on UL191 and spending 12 hours landside until JL’s counter in DEL opens.)