I have one Heart of the Blossoming Flower me and might get more from the Whale Shop.
I only have Five 6* Girls and they are Blossomed. So my question is "Which 5* Girls are the strongest/Get a bloom form?"

For people saying save them for 6*, not going to spend money/my luck is bad with the Gachas.

depends on what you are seeking. power or waifu.
if it's power, i would recommend you to wait for more rainbows and spare them.
second affection gifts are rare anyway.

Ew. Do I really need to make a bloom thread for golds too?

The rainbow thread took long enough to make on its own. You guys really can't do your research on these things?

Just bloom your waifus, don't stress the stats. This isn't that kind of game, and I don't understand people who pass up on "lower tier" units just because their stats or abilities aren't up to par. Unless it's Iris. Fuck her.

Of the blooms we currently have available-ish, I'd probably focus on Bipinna Cosmos or Lavender first. If only to replace their garbage evo art with their superior bloom art.

If I were going to bloom any 5* I'd go with ones that I know I'll make frequent use of, i.e. whaleship.

So probably Chocolate Cosmos and Strawberry Candle first, and while I love Poppy, she doesn't exactly stand out in terms of usefulness with respect to unique capabilities for whaleship. Also, no bloom art for her as of yet.

It's really a matter of which gold is your waifu or which golds you frequently use, or which golds you would REALLY want to bring on your Whaleship for their stage buffs.

First one, only you can answer.
Second one, this reply I posted to a similar question just over a day ago might be helpful. But, look through your squads and decide which units you feel are really important.
Third one would be Chocolate Cosmos, Lantana, Strawberry Candle or one of the following:
Convallaria, Tree Peony, Rose, German Iris or Allium. Maybe not in one of your front-squads, but starting with 20%-30% on your Solar Beam is still very useful on the whalemaps, so might as well make the best of those units.

Pretty much wut Drop said

For me, Chocolate Cosmos - waifu and chocolate nodes

Lavender - strongest loli in my army

Peach - strongest 5* (big boobs) in my army w/o ampy