Well, the fifth largest ETF in the US is the sharply named QQQ which exclusively follows the Nasdaq-100 index. Everything larger tracks a broader domestic index like the S&P 500.[0]

Listing on the LSE relegates you to "international" funds, which make up a third or less of most portfolios. These have historically lagged US fund performance, quite significantly in the last ten years.[1]

[0] https://www.etf.com/etfanalytics/etf-finder

[1] https://www.morningstar.com/stocks/revisiting-case-internati...

There are costs to working on different exchanges and out of country exchanges.