Check out this issue if you use Windows. Mica for Everyone is known to play decently, but be very spotty.

Albeit not out of the box, (and very much intentionally so), this theme supports translucency in some areas.

You can achieve the same look on Vencord/macOS by doing as follows:

• Go to Settings > Vencord, then toggle "Enable Translucent Window".

• Assuming that the entire surCord.theme.css contents are in QuickCSS:
  • Paste @import url('https://slippinggittys-discord-Themes.github.io/surCord/src/fixations/additions/translucency.css'); underneath the source @import, as demonstrated so bellow

Extra info

• You can adjust the oppacity and colors by pasting & messing with these varriables

.theme-dark {
 --background-tertiary: #2f31364b;
}

.theme-light {
 --background-tertiary: #ffffff1d;
}

Also see Acorn, an Accord inspired theme based on surCord made specifically for Vencord + macOS

• You can very easily change the accent and theme color for surCord by navigating to /src/_theming.scss and uncommenting >>>one<<< of the accent colors and one of the background colors.

  BD and Stylus can uncomment these in surCord.theme.css / surCord.user.css

• You can set surCord to use Apple's Emoji font

  • Navigate to /src/_modules.scss and uncomment @import url(https://mwittrien.github.io/BetterDiscordAddons/Themes/EmojiReplace/base/Apple.css);

• You can uncomment font-weight: bold !important; in your respective font sections
  to use San Fransisco Display Bold. (Or specify your own weight, 100-900; bold = 700)

  • BD: surCord.theme.css
  • Replugged/Powercord: /src/_font.scss
  • Stylus: surCord.user.css

• Stylus users on Firefox have to be on version 102 or later and toggle "Patch CSP to allow style assets"
  Chromium browsers shall be fine by default on any recent version.