The alternative to reverting to using Fixed assets for investments is to use Manager versions after v24.05.10.1523 and before 24.6.8.1635 which does handle realised and unrealised gains/losses.
The only issue with that implementation as most investors would want to minimised realised gains (maximising unrealised gain) to minimise capital gains tax when selling some of the investments. This involves selling the investments purchased at the highest price first. A strategy not supported by Manager atm.
https://www.ato.gov.au/individuals-and-families/investments-and-assets/capital-gains-tax/shares-and-similar-investments/keeping-records-of-shares-and-units