Pepp I mostly agree with what thmf said. I haven't tested silentlink specifically, but foreign eSIMs do work. After the first connection to Russian cell towers, you have to wait 24 hours before your cellular network and SMS become functional. If your phone is turned off for more than 72 hours, the cellular providers assume you left Russia and have returned, so you'll need to wait 24 hours. Depending on the region and the current situation with drone attacks, this rule may or may not apply. Occasionally, even if the phone is off for less than 72 hours, the block can still be enforced.
VPNs work, but there are many limitations. You'll need to test different VPN providers, protocols, censorship circumvention methods, server locations, ports.
I recommend preparing an innocent phone for crossing the border. It may be searched, and FSB officers could examine whom you chat with, who you follow on social networks, what photos you've taken, and who you've sent money to. They utilize a Cellebrite-like system named "Мобильный Криминалист" for forensics. Finally, I'd advise against visiting Russia purely for tourism or leisure. The current situation could land you in jail for no reason.