Some quick question for solution manager in 2 system landscape

First of all is there any way to not implement Solution manager but to still be able to patch the system.?

i really need it only for this.

If there is no way to avoid the solution manager, tell me is the saprouter the only way for connection to SAP for the patches download. I don't need anything else for now.

IS there a way to use a direct connection to SAP,?

do the sAP router has to have 2 NICs where one is the public and one the private IP?

i need to solve this one quickly so any help would be appreciated

Thank you in advance!