Thank you, @helomech. I went back to look at two reviewers whom I have listened to more closely: Soundnews and iiwi. Soundnews rated the A8's dedicated line amp section very highly and considered the DAC section as good as the Gustard A26 (another sota). These two components, together with the already excellent digital streaming section, make the A8 stand out and pull ahead of everything else at a similar price point of $2k. However, despite giving similar high marks to its streaming section, iiwi has concerns about its preamp section, even stating that it becomes a limiting factor to the overall performance of the A8. As far as the DAC section goes, iiwi believes it is comparable to around $1k DACs in the market, with the Gustard R26 outperforming it.
Based on these disparities in listening tests, I am not sure if the AIO A8 is readily a replacement for your BM LA4. However, as we know, listening tests are subjective, and objective measurements could easily counter those qualitative evaluations if one chooses to trust the measurements. I also previously owned the E70V, and I liked it initially but returned it after more extensive auditioning later. It is indeed the first Topping DAC that I had which provided 'some' soundstage depth that I am craving. Just my two cents.