Country boundary rendering slowly in openmaptiles

Hi For larger audience, posting here too(https://github.com/openmaptiles/openmaptiles/issues/495 ).

I am using openmaptiles for setup own vector tiles server. By default, it shows incorrect india boundary. So i have created a layer in my stye.json using geojson data of all countries boundary data(with updated india boundary).

But its taking too much time to render boundary line. Also tried as trimmed geojson data(now 1.6mb), but still its rendering very slowly.

Any alternate options?

Note: Tried to solve as, render country boundary using openmaptiles boundary data for all countries except india. Then add layer using geojson for india boundary only. But i cant disable to rendering boundary for india using openmaptiles boundary, as they are not providing country code or name with boundary data.