I do try 🙂.
I’m delighted that I’ve been able to offer something helpful - even if unable to provide a direct solution on iPad.
Perhaps, whilst acknowledging the [beneficial from a security perspective] limitations of you iPad, you might focus your import efforts on what can be achieved at the desktop of a PC or Mac. If you can import bookmarks into a desktop browser, you’ll usually find that the equivalent iOS/iPadOS App has an ability to synchronise its bookmarked links.
For example, Firefox (available across many platforms, including Apple) will sync’ both bookmarks and logins/passwords via your FireFox account. Thus, if you can import bookmarks externally, they can be synchronised to FireFox on your iPad.
Similarly, if you can import bookmarks to Safari on a Mac, they too will synchronise with your iPad via iCloud.
Maybe there is something here that you can explore.