On the face of it, obviously it is not great and your numbers...

On the face of it, obviously it is not great and your numbers are correct of course. I am have been a holder for a couple of years now and recently purchased some more. While this hasn't been the best short-term investment, I am happy to hold for the longer term.
No investment should be viewed at a specific year, or point to point, without a more detailed investigation.

For FY22, BTI outperformed the benchmark by 46%. Yep, 46%!!
You can look at the FY22 AGM Presentation to see this. It was in no small part due to the benchmark having a awful year, being down around -30%.

Now that is an outstanding result for FY22, but no one should have expected the outperformace of the benchmark to continue, although I did check FY21 and it also outperformed the benchmark in that year, by 49.4%.

Those Managed Funds that you mentioned that are "getting 20 to 30%" for FY23 would have had a -20 to -30% for FY22. I know because I own a few of them (HYGG was -32.7% for FY22 and up until the end of May this year, the one year return was 21.7%). So a similar story to the ASX All Technology Index benchmark.

Over the period of 2 and 3 years, BTI has outperformened the benchmark by 8.0% and 18.6% respectively. So that is nice to see.

Importantly, the portfolio returns for 1, 2 and 3 years have been 2.6%, 9.8%pa and 12.9%pa respectively.

With a post-tax NTA of $1.52, BTI is trading at a 23% discount to NTA. This leaves plenty of room for things to go wrong and still not have the share price react negatively over a long period. I know this discount has historically been the case, but there is not much that can be done about it. Personally I am happy with David Kirk and Paul Wilson are managing the company. Let's see what the next 1, 3 and 5 years brings.