I created a Russian right-handed layout dividing the alphabet into 2 parts simply by the frequency of use.
о е а и н т с р в л к м д п у я
ы ь г з б ч й х ж ш ю ц щ э ф ъ
L0
.
уеслд,
ионтвк
яармп
L1
.
жйчшэ,
ьгбзыю
щхцфъ

It turned out that all the main vowels on the index finger. Well, it seems like a compromise, I can't imagine anything better.
I can't test it in practice yet, but I'm satisfied with the result in general. It seems that I will stay with this variant for now.
Here are the efforts I have made.
# Name ξ ρ x y f g α s # Zahlenreihe/number row
# Taste AE09 10 0 8.75 0 +3 - 20 - # 9
# Name ξ ρ x y f g α s # Obere Zeile/upper row
Taste AD06 8 1 6.25 1 +2 - 4 - # Z
Taste AD07 9 1 7.25 1 +2 - 2 - # U
Taste AD08 10 1 8.25 1 +3 - 2.5 - # I
Taste AD09 11 1 9.25 1 +4 - 5 - # O
Taste AD10 12 1 10.25 1 +5 - 8 - # P
# Taste AD11 13 1 11.25 1 +5 - 20 - # Ü
# Name ξ ρ x y f g α s # Mittlere Zeile/middle row
Taste AC06 8 2 6.50 2 +2 - 2 - # H
Taste AC07 9 2 7.50 2 +2 + 1 - # J
Taste AC08 10 2 8.50 2 +3 + 1,5 - # K
Taste AC09 11 2 9.50 2 +4 + 2 - # L
Taste AC10 12 2 10.50 2 +5 + 3 - # Ö
Taste AC11 13 2 11.50 2 +5 - 6 - # Ä
# Name ξ ρ x y f g α s # Untere Zeile/lower row
Taste AB06 8 3 7.00 3 +2 - 6 - # N
Taste AB07 9 3 8.00 3 +2 - 2 - # M
Taste AB08 10 3 9.00 3 +3 - 4 - # ,
Taste AB09 11 3 10.00 3 +4 - 6 - # .
Taste AB10 12 3 11.00 3 +5 - 12 - # -
# Taste AB11 13 3 12.00 3 +5 - 50 - # S
# Name ξ ρ x y f g α s # Leerzeichenzeile/space bar row
Taste SPCE 7 4 7.00 4 +1 + 0 # Leerzeichen/space
ShiftL LFSH 0 4 0.00 4 -1 - 2 # Shift links/left
ShiftR RTSH 8 4 8.00 4 +1 - 2 # Shift rechts/right
So I am generally satisfied with the Russian layout, but I will be glad to hear your critics or hints. But I am much more interested in the English keyboard layout now. I don't have an English corpus, but I will try to make it according to your recommendations above.
First of all, it is necessary to determine what frequency of English letters to choose for my task, as here:
https://www.sttmedia.com/characterfrequency-english#letters or another variant
http://letterfrequency.org/ ?
The most common variant of the frequency of English letters that I found:
e t a o i n s r h l d c u m f p g w y b v k x j q z
Secondly, I need to divide the alphabet into two parts. My keyboard will consist of 18 keys. Except for the alphabet it is necessary to appoint a statically dot and a comma irrespective of layers in general. In Russian layout opt has defined to me such places for a dot and a comma (keys are allocated by grey-blue):

The dot is on top. The comma is on the right. I have moved one key from the bottom of the pinky to the top of the middle finger on the keyboard scheme since the last post.
I also need to add an apostrophe to the English alphabet. In Russian there is no apostrophe, or rather the role of an apostrophe is performed by two letters(ь and ъ). Therefore, the apostrophe can be considered non-static ("Zeichen"), not static ("FixesZeichen"). I do not know the frequency of the apostrophe in the English language, to place it on the first layer or on the second. In the Frogpad layout the apostrophe is on the first layer, but in my configuration file I defined it on the second layer.
As a result it turns out that in total 18 keys for symbols. But the dot and the comma should be appointed statically for both layers. In addition, I need to add an apostrophe here.
Ian, I will have to collect the English corpus for a long time. Maybe you can help me to make an English layout for my configuration? In the attached configuration files I have divided the alphabet as follows:
e t a o i n s r h l d c u m f p
g w y b v k x j q z '
There are 16 keys and a Space and two Shifts(I didn't include a dot) and a comma).
I'm not sure I've correctly assigned the letters. I also decided to exclude a dot and a comma from the calculations at all, because I determined their location when calculating the Russian layout. If you calculate my configuration on my case I will be very grateful to you. Perhaps you will not like something and you will change something. I do not insist on anything on 100%.
Thank you.