How can I seal liftgate wiring to prevent water?

[stiglitz]

Installed a new liftgate/hatch for my hatchback. All the tabs of this plastic ring from the donor hatch are broken. This results in the rubber boot/wiring/plastic ring to be loose and not form an adequate seal to keep water out.

I don’t want water getting in and soaking my headliner. What should I do? I can’t replace the plastic ring with a new one; the opening of the ring is not big enough for the wiring harness connector to pass through. This is where the wiring is located, for reference: https://imgur.com/a/Z7vLU8n

Maybe use some silicone???

I am on mobile. The photo should be rotated 90 degrees clockwise.