Just saw this thread and wanted to jump in because I spent way too much money when I first got my a7 IV. Honestly, you can get incredible results without buying the most expensive gear out there. Here is what I found works for a budget-friendly setup:

• Skip the CFexpress Type A cards if you arent shooting high-bitrate S&Q. I use the Lexar Professional 1667x 128GB SDXC UHS-II and it handles 4K 10-bit 4:2:2 just fine for way less cash.
• Instead of a pricey monitor like the Ninja, I just use the Monitor+ app on my phone with a basic cold shoe mount. It works well enough for checking focus when I am solo.
• For lenses, the Samyang AF 35mm f/1.8 FE is a total steal. Its super light for gimbal work and the autofocus is surprisingly snappy on this body.
• Dont forget about audio. The internal mics are kinda thin, so I grabbed a Rode VideoMicro II. It doesnt need batteries and sounds miles better for under a hundred bucks. Basically, the camera itself is the biggest investment... you can definitely save on the extras and still get that pro look.

Been using the a7 IV for about a year now and honestly, I'm still very satisfied with it. It handles professional work easily without needing the most expensive rigging.

• Feelworld F6 Plus 5.5 Inch Monitor is a great budget alternative to a Ninja V if you dont need external recording and just want a bigger screen.
• ProGrade Digital 128GB SDXC UHS-II V60 cards work perfectly for 4K 10-bit and save you a ton over V90 or CFexpress. One quick tip... make sure you set the Auto Power OFF Temp to High. It keeps the camera from cutting out during long 4K clips. Also, download Catalyst Browse. Its Sony's free tool that uses the cameras gyro data to stabilize footage in post. It looks way better than standard IBIS and doesnt cost a dime. The official Sony Help Guide website is also a much better resource than most people realize for checking specific bitrate compatibility.

Here are some recommended settings and tips for capturing high-quality 4K footage:

Picture Profile & Creative Style

• S-Cinetone is a great picture profile that gives a filmic look right out of camera. Alternatively, S-Log3 provides the most dynamic range for color grading flexibility in post.
• For creative styles, Standard or Neutral work well. Avoid styles like Vivid that overly saturate colors.

Exposure Settings

• Aperture: Use the sweet spot of your lens, typically around f/4-5.6, for sharpness. Open up more if you need a shallower depth of field.
• Shutter Speed: Follow the 180-degree shutter rule and double your frame rate (e.g. 1/50 for 24fps, 1/120 for 60fps).
• ISO: Keep it at the native ISO 640 when possible. Don't be afraid to raise it in low light, the a7 IV performs well at higher ISOs.

Focus Settings

• Use AF-C focus mode for moving subjects
• Flexible Spot M or Zone focusing areas work well for most scenes
• Face/Eye detection is excellent if shooting people
• Manual focus when critical focus is needed or for tricky subjects that confuse AF

File Format & Record Settings

• XAVC S 4K 4:2:2 10-bit is the highest quality codec
• 24fps or 30fps are standard frame rates. 60fps/120fps are great for slow motion
• Long GOP compression maximizes record time, All-I is easier to edit

Other Tips

• Use an external recorder like the Atomos Ninja V+ to capture ProRes RAW
• Invest in good lenses - they make a bigger difference in image quality than the camera
• Get a cage, external monitor, ND filters to complete your video rig
• Record audio externally (e.g. XLR mic into recorder) for best sound

Those settings and accessories should allow you to get some great looking and sounding footage out of your a7 IV. Experiment with the settings and see what works best for your shooting style and needs.