Adaptive Icon
First of all, don’t uncheck the icons in deployment and don’t change the manifest.
1) Add your icons in .png format in Project Options normally. This is necessary to keep the compatibility with android 7.1 and oldest.
2) You need to create 3 files "ic_launcher.xml", "ic_launcher_background.xml" and "ic_launcher_foreground.xml"
3) ic_launcher.xml example:
<?xml version="1.0" encoding="utf-8"?>
<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
<background android:drawable="@drawable/ic_launcher_background" />
<foreground android:drawable="@drawable/ic_launcher_foreground" />
</adaptive-icon>
Add it in deployment with remote path "res\drawable-anydpi-v26"
4) ic_background.xml example:
<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:width="108dp"
android:height="108dp"
android:viewportWidth="108.0"
android:viewportHeight="108.0">
<path android:name="square"
android:fillColor="#ff3657f4"
android:pathData="M0,0 L108,0 L108,108 L0,108 z" />
</vector>
Note that I fixed a solid color (#ff3657f4), but you can put gradients in this xml or an image in place the background (not recomended).
Add it in deployment with remote path "res\drawable"
5) ic_foreground.xml example:
<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:width="108dp"
android:height="108dp"
android:viewportWidth="108.0"
android:viewportHeight="108.0">
<path android:name="square"
android:fillColor="#ffffffff"
android:pathData="M 53.91,32.73
C 54.35,32.75 54.49,33.06 54.75,33.39
54.75,33.39 56.18,35.17 56.18,35.17
56.18,35.17 62.30,42.80 62.30,42.80
62.30,42.80 65.32,46.57 65.32,46.57
67.71,49.56 69.15,51.35 69.99,55.19
70.19,56.06 70.35,56.97 70.35,57.86
70.35,60.63 70.34,61.92 69.39,64.60
67.61,69.60 63.19,73.48 58.06,74.76
56.05,75.26 54.85,75.23 52.81,75.20
51.89,75.19 50.64,74.92 49.74,74.70
44.14,73.29 39.76,68.84 38.20,63.31
37.95,62.41 37.66,60.97 37.65,60.04
37.62,57.15 37.69,55.37 38.79,52.61
39.86,49.91 41.15,48.49 42.92,46.27
42.92,46.27 48.17,39.73 48.17,39.73
48.17,39.73 51.98,34.98 51.98,34.98
52.41,34.44 53.40,33.04 53.91,32.73 Z
M 46.57,58.86
C 46.57,58.86 43.70,58.86 43.70,58.86
43.70,58.86 43.70,59.45 43.70,59.45
43.70,63.37 46.54,66.93 50.04,68.42
50.88,68.79 51.80,69.02 52.71,69.13
53.27,69.20 53.36,69.10 54.00,69.26
54.00,69.26 54.00,66.29 54.00,66.29
52.87,66.29 51.97,66.13 50.93,65.66
48.53,64.57 46.57,61.94 46.57,59.25
46.57,59.25 46.57,58.86 46.57,58.86 Z" />
</vector>
You can change the white color (#ffffffff) and the pathData. Note: this pathData is the same path data inside the .svg. If you have your icon in .svg, just open it in notepad and copy the "d" field inside the "path" to the pathData of xml (only if the svg has size 108x108).
Add it in deployment with remote path "res\drawable"
Result
(the low quality is due to the gif format)
Extra
You can do the same with the splash screen (vector splash screen). The vector splash screen works in all android versions supported by Delphi.