Zeihan is a strange guy who seems to take a lot of his information from online discourse, which is a poor substitute for first-hand knowledge. The ground truth is very blunt: Russia has not bothered to install even a chain-link fence along its European border. Some sections have a sand strip to detect crossings, others not even that, most of it looks like this: https://freepages.rootsweb.com/~hughwallis/misc/FIRU/DSCN237... Mushroomers and other foragers often get lost and end up walking into Russia (and vice versa) without even realizing it. This is such a regular occurrence that it receives only warning or a small fine, and a few sentences in local newspapers.
A counterexample comes from post-2022 Finland, Estonia, Latvia, Lithuania and Poland: every single one of them is digging anti-tank trenches along the border with Russia, installing everything from surveillance systems to reinforced bunkers and pillboxes, preparing minefields to be laid and bridges to be blown up. Things have gone so far that some of them are discussing dismantling railway lines connecting with Russia to prevent them from being used by invading forces.
No such preparations can be seen on the Russian side of the border, because in the post-Cold War world, everyone recognizes that an attack from Europe is a delusional fantasy. There's no will and no means for that.