I was formally educated to do low level development, did operating systems, hardware design, and communications for a living for 15 years. During that time I also learned and regularly used FP, data processing, windows GUI, full stack web development. Every year I pick a new tooling language so that I'm not completely tied to one language or paradigm. Every time I have an opportunity to use the right language or tool for the job I learn it and use it.
The whole point of my education process was not to learn C and Assembly, it was to motivate me to he constantly learning. When I wanted a new job I created a "real world problem" to solve, did actual design docs, took courses online, read books, etc. Was able to get a new job in a completely different field, doubling my pay and reducing my work load. That's all due to the fact that if I had a list of stuff I didnt know I'd be out there learning that stuff every waking minute.
I would immediately try to get you fired for lying about your knowledge and qualifications.
One of the best possible things you can do is admit when you don't know something. That should always be safe to do at any GOOD employer.