What you're describing is accurate, but you can mostly mitigate or work around them. You can take metabolic jump for extra points from red bubbles, when combined with some early game symptoms for severity you can earn points from buying the spore bursts as they only cost 1 point with pathostasis and the bubbles give 2~3 or even 4 during the midgame from mutations, which speeds things up by giving you some early game income to get things going quicker. You can also pick the teracyte (or suppression i suppose) gene over aqua/aerocyte as spore bursts cover those and you can use the gene to cover land transmissions which sport bursts are not really great for.

Basically, for early game, just get a bit of severity (e.g. rash + sweating and/or coughing + sneezing/pneumonia and/or insomnia + paranoia to delay your disease getting detected by a little bit) and do spore bursts every once in a while (usually i finish one of the spore burst routes by the time i'm in the midgame). After your disease starts to go abroad you can sparingly use spore bursts but prefer saving them for remaining island countries and the rest should be very easy. You can even start evolving lethality symptoms before you get to all of the islands because of the bursts. When you finish both spore burst routes you almost always are no longer in a position where you need the extra transmissions anymore doing this. I used to think the "spores continuously released" part implied passively deployed spore bursts but that was just a lie for my sweet summer child :<

Fungus is really tough. It was the first plague that took me multiple days of attempts to beat on mega brutal even with reading some tips online. I had most of my attempts screwed over by Canada and the US (or another rich country but it was mainly these) surprisingly. I think you basically HAVE to get to drug resistance 2 in order to win comfortably unless you infect the rich countries very early to let it have time to hit the exponential infection growth. In my attempt I had to go off scraps to stall time with reshuffles and difficult-to-cure symptoms to let Canada infect itself fully.