Can I hide the candles under a footprint or TPO and keep the price line?

Yes. With the footprint or TPO chart type, turn on Hide bars in the chart type selector. It keeps the price line, the countdown and the bid and ask.

Yes. Switch the chart type to Volume Footprint or Time Price Opportunity with the chart type selector next to the interval chips, then turn on Hide bars in the same menu. The candles disappear, and the price line, the countdown and the bid and ask stay.

Hide bars works with the footprint and TPO chart types only.