They did - and those guidelines are reasonably clear. Example:
“The gatekeeper shall allow business users, free of charge, to communicate and promote offers, including under different conditions, to end users acquired via its core platform service or through other channels, and to conclude contracts with those end users, regardless of whether, for that purpose, they use the core platform services of the gatekeeper.”
👉🏻 Allow communication and concluding of contracts with end users. Without using the platform services of the gatekeeper. Free of charge.
It‘s not. It‘s not hard to comply.