swingaling

I've got some safari trips coming up (in 3-4 mos) and I've decided to invest in a telephoto zoom lens. I generally travel very light with an iPhone as my only camera, but I realize it will be entirely inadequate for wildlife/safari use. For the upcoming safari trips, I'm looking for something more capable. Here's the dilemma.

I currently own an OM-D E-M5 (from 2012) and various lenses; the longest being a slow, cheap 40-150mm zoom. In the past I used this camera for street photography, but with the huge advances in iPhone cameras I've found myself using it less and less. The lens I used most often is a great 17.5mm f0.95 lens (for street photography and low light situations). Since I'm planning to do some wildlife photography, I'll need a lens with a lot more reach. I've (more or less) settled on a 100-400mm lens.

Option 1 - M43: Panasonic 100-400mm f/4-6.3 OIS ($1,800) + new m43 body -- $3,000
This is the obvious choice since I already have a m43 body, but it's a bit pricey for what it is, frankly. The reviews are mixed, with reports of the mounting flange being fragile (and not repairable if broken). Additionally, given the age of my body, I'm considering an upgrade for that as well (for various reasons). A new G95 body would be an additional $1,200. The concern with going this route is the generally poor mid-high (1,000+) ISO performance and middling AF with m43 bodies (the E-M5 in particular). The low light performance can be really annoying.

Option 2 - FF: Sigma/Tamron 100-400 ($600) and Canon RP ($1,200) -- $1,800
I'm seriously considering this instead. The reviews of this lens are pretty good and this combo will certainly give better high ISO and AF performance. A FF body is a lot more versatile in terms of glass.

Size: I like EM5 for travel due to size/weight, but the RP is actually the same size/weight as the E-M5 (body+batt+grip). The situation with lenses is similar. The Sigma is 1,160g and the Panny is 985g; overall dimensions are similar as well.

Alternative FF lens: I've read great reviews of the Canon EF 100-400mm II lens, but it's at least triple the cost of the Sigma with nowhere near 3x better performance. It's also 500g heavier.

While on safari, I plan to use my iPhone for wide angle and the MILC (EM5/RP) for more reach. I likely won't bring a second lens for the camera, but if I do, it would be a small wide prime.

Thoughts? Currently leaning toward the Sigma/Canon combo. Should I consider a bridge camera? I'm a bit undecided on what I should do, so I'm looking for input/suggestions.