Film Photography in Egypt (and slide film?)

Hello!

I am looking for some advice before an awesome adventure I have planned!

I'm bringing my Canon EOS 300X SLR (full frame 35mm) to Egypt in September. I'm still a novice, but I'm currently trying to teach myself manual mode.

I'm bringing Canon EF 24mm and 50mm prime lenses (both f2.8) and plan to pick up a gradual neutral density (GND) filter because I read that it's necessary if you plan to shoot colour reversal (slide film).

I'm planning to bring a bundle of Kodak Gold 200, Kodak Ultramax 400, and Kodak ColourPlus 200 from Analogue Wonderland (UK). I also want to buy some CineStill 50D and Fujifilm Velvia 50, which is a colour reversal (slide) film. Various websites and YouTubers explain that this is quite difficult to correctly expose. One needs a GND and a good spot light meter reading to have the best chance of correctly exposing slide film. However, in spite of these difficulties, it's a truly beautiful film and I think that parts of Egypt would just look incredible captured on it!

I'm planning to take photos during the day, throughout the day (dawn to dusk). I know street photography isn't generally well-received in Cairo, so the majority of my subjects will be landscapes: canyons, beaches, horizons, desertcapes, and architecture.

I am wondering whether I should rather shoot slower colour negative ISO films (like 50 and 100) for the duration of the trip? I read that it's better to overexpose colour negative film due to the forgiving latitude. However, Egypt will have bright, blazing sunlight for the majority of my photography time and I wonder if overexposing 200 or 400 ISO is overkill as they will already be letting in lots of light?

I don't know much about manual mode yet. I'd like to understand more about the Sunny 16 rule and the Ansel Adams scale before I try to shoot the Velvia 50 colour reversal. My partner is bringing a Sony A7iv mirrorless camera, so I'm thinking I could also use that as a guide to correctly meter my own shots if I'm stuck. I'd also like to grasp the elementary basics for shooting the colour negative rolls.

I've been shooting colour negative film on my travels since 2009 with fairly okay results that I was happy with (just using Auto and random scene presets), but this is the first time I'll be intentionally shooting 35mm film on manual mode. If anyone has any tips about shooting film (both colour negative and reversal) in a place such as Egypt with bright blazing sun and immense landcapes, I'd love to hear them! :)