I have the impression that a lot of people are interested in seeing the development of total amount ETH locked on L2 in a chart, and not only TVL. TVL in USD or ETH is very dependent on the price action, while looking at total stablecoins or total ETH (or any other coin) would give a chart that describes L2 adoption without the noise of price action.
This would be quite easy to implement since you already have the data needed. One solution could be that one could choose which coins one wants to include in the TVL displayed i.e only choosing ETH, USDT (or a category stablecoins) or OP.