Regardless of whether the Wi-Fi network you connect to is publicly connectable or not, the administrator of the network cannot view the contents of your browsing traffic as long as the website uses HTTPS, which most websites, including this one, do. You can verify this by looking for a padlock symbol to the left of the website address or https in the website address. Claims that they are insecure are outdated claims made by VPN companies to scare people into paying for their expensive service.
About the security of public Wi-Fi networks...
"Attackers on the same network can easily intercept sensitive traffic, capturing login credentials, emails, or private messages using simple software tools." - HTTPS, along with HSTS, which most sensitive websites use, make this impossible due to mandatory encryption.
"Hackers can set up a fraudulent Wi-Fi access point with a legitimate-sounding name. When users connect to this evil twin instead of the real network, all their data passes directly through the attacker's device, allowing them to monitor activity and steal sensitive information without the user knowing they are on a fake network." - Again, as in the previous misconception, HTTPS along with HSTS makes this impossible.
"Because the network is public, there is no barrier preventing an attacker from joining. Once connected, they can use readily available software to position themselves between the user and the websites they visit. This allows the attacker to relay and potentially alter the communication between the two parties, making it possible to inject malware into the connection or steal session cookies to hijack logged-in accounts." - Again, HTTPS along with HSTS makes this impossible. HTTPS is used by 89.1% of all websites.
"Tools used by network administrators to diagnose traffic (like packet analyzers or sniffers) can be used maliciously on unsecured public Wi-Fi. Because the network is shared, anyone on that network can potentially capture data packets being sent by other users. If a user visits a website, an attacker can see that data." - Again, HTTPS and HSTS make this impossible.
"An attacker on the same network can see all files stored on your computer." - Modern operating systems use a public network profile when connected to public Wi-Fi which, yet again, make this impossible.
These misconceptions have been historically true but instead of VPN companies saying they are not now due to modern security advancements they continue to weaponize them to boost their own revenue. As long as you don't enter anything on a website your browser marks as "Not Secure", you'll be fine.