Standard HTTP Update URL possible for IP linking?

I’d like to use Nextdns with a Peplink Balance One router being connected to 2 WAN lines of different providers (WAN1: LTE + WAN2: DSL -> balancing router). Both WAN internet providers support only IPv4. So I need to use 2 Nextdns profiles - one for every WAN - and IP linking for each of them to use Nextdns as intended.

Unfortunately Peplink does not support either nextdns directly nor running a separate dns or dyndns script, yet.
However, what I can do is configuring a HTTP-URL for each WAN that the Peplink router uses for health checking of a WAN (detects connection being online). See screenshot above.

Nextdns expects the automated IP update to be carried out via an HTTPS-URL like this example:

https://link-ip.nextdns.io/[Profile-ID]/......

Unfortunately Peplink doesn’t support the usage of HTTPS, only HTTP for health checking.
Typing the above shown example URL with prefix HTTP (e.g. http://link-ip.nextdns.io/[Profile-ID]/......) is not working. Reason is that Nextdns forwards to HTTPS immediately and Peplink cannot deal with such an https- (non plain text) reply.

So I’d like to ask if you could maybe provide or accept an HTTP-only URL for updating linked ip?