So, I know oem retrofit will be almost impossible. What are my options for upgrade?

1. LED bulbs? I tried this option from an Amazon brand that I used in many cars before but the Mini didn’t like them. They started flashing and I got error codes.

2. AfterMarket Headlights? Are they any options? I saw ones on eBay from China. Any other options?

 

Uprated halogen bulbs - Philips +130% or +150%. Sylvania, Osram etc have similar but they don't last as long.
Are they H7?

 

I did upgraded to Phillips and while better than the oem bulb isn’t good enough

 

I think the OEM bulb is an H4? If I were in your position, I would try the new Morimoto 2-Stroke 3.0
https://www.theretrofitsource.com/h4...-H4?quantity=1

I've been watching a bunch of comparisons on YouTube, and these have been getting some good reviews.
https://www.youtube.com/results?sear...o+2+stroke+3.0

 

Yes! Those videos are worth watching. Finally, an LED headlight bulb has been designed that actually works. (Bulbs are too rich for my wallet, though!).
Meanwhile, you might check the alignment of your existing lights - just point them at a brick wall & bring them up half-a-brick.

 

The bulb on the F54 doesn’t allow for any excess on the back of the bulb. There is no space for anything else that a regular size bulb.

I tried an LED bulb and it started flickering badly with an error message

 

What is the bulb type? H4?
If they flickered when you first put the key in, that's just the hot & cold bulb checks that can be coded off.
When the headlights are switched on, they should not flicker.
(I've tried a couple of not-Morimoto LED H7 & H1 bulbs & they were awful = dim, glare, no range, etc).