Approach to build google map based app with custom markers (two ways)

I am developing a map based app, my first choice has been Google Maps JS Api (!/). In my case I need to add a marker with a custom image with a number wrote on it. This is easy to implemente with the JS api, I can use markers directive (!/api/markers) using options property with laberAnchor, labelClass and labelContent.

options: {
	//animation: 1,
	labelAnchor: "15 38",
	labelClass: 'foo-class foo-class1',
	labelContent : '<div class="foo-marker"><div class .. ...</div></div>'

But I am experimenting slow performance in the device (I use a tired moto g 2ยบ gen).

So I am discover a native way with: But the problem is with that API I cannot add HTML code to the markers,

What I can do to build a custom marker with a image wrote on it with this API?

And other question that I have got, Is there this problem if I use the official maps SDK developing with Android (java)?

I think to compose an image, save it to the disk and then load it in the map.

Thank you.