On 15 March, 2020, Israel’s Ministry of Health updated their guidelines. The mikva’ot that adhere to their guidelines remain safe for immersion, except in cases in which women are at high risk.
They now recommend that women perform all
preparations at home, arriving at the mikveh just for a quick shower and
immersion itself. If you complete your preparations (or take a follow-up quick shower) right before leaving home for the mikveh, then you can just check yourself there in the mirror for possible
chatzitzot and immerse. In that case, you should dip once in the mikveh itself to wet your hair before your usual immersions.
Please note that a woman can always prepare with a thorough shower, as opposed to a bath, as necessary.