Simple script to convert markdown bold text to Unicode 'bold' characters. You can exend the script with other ranges (like bold AND itatic) (explore chars after and properly before 119808(A) .. 119859(z)). This can be used for formatting Facebook text.

markdown_to_bold.py

import re

text = "Today’s world is driven by **technology** and **connectivity**, reshaping interactions and work. **Environmental issues** and social change call for urgent, **collective action** toward sustainability."
## Output: Today’s world is driven by 𝐭𝐞𝐜𝐡𝐧𝐨𝐥𝐨𝐠𝐲 and 𝐜𝐨𝐧𝐧𝐞𝐜𝐭𝐢𝐯𝐢𝐭𝐲, reshaping interactions and work. 𝐄𝐧𝐯𝐢𝐫𝐨𝐧𝐦𝐞𝐧𝐭𝐚𝐥 𝐢𝐬𝐬𝐮𝐞𝐬 and social change call for urgent, 𝐜𝐨𝐥𝐥𝐞𝐜𝐭𝐢𝐯𝐞 𝐚𝐜𝐭𝐢𝐨𝐧 toward sustainability.

# text = "_000 **A** 111 **b** 222"

def convert(text):
    
    # Split input to couple of 'normal' and 'bold'
    # Process each couple, then continue with remaining text
    
    rex = r'(.*?)\*\*(.*?)\*\*'
    
    result = ''
    while True:
        # Find couple
        match = re.match(rex, text)
        
        # No more match, combine remaining with previous result.
        if not match:
            result += text
            break
        
        # 2. For each bold range, convert them to 'bold' format
        groups = match.groups()
        normal = groups[0]
        bold = groups[1]
        
        # Transformed of `bold`
        t_bold = ''
        for ch in bold:
            # Bold A..Z <--> 119808..119833
            if ch >= 'A' and ch <= 'Z':
                ch = chr(ord(ch) - ord('A') + 119808)
            
            # Bold a..z <--> 119834..119859
            elif ch >= 'a' and ch <= 'z':
                ch = chr(ord(ch) - ord('a') + 119834)
            
            t_bold += ch
        
        # 3. Combine ranges back as original string.
        text = text[match.span()[1]:]
        
        result += (normal + t_bold)
    
    return result


converted= convert(text)

print(converted)

## Today’s world is driven by 𝐭𝐞𝐜𝐡𝐧𝐨𝐥𝐨𝐠𝐲 and 𝐜𝐨𝐧𝐧𝐞𝐜𝐭𝐢𝐯𝐢𝐭𝐲, reshaping interactions and work. 𝐄𝐧𝐯𝐢𝐫𝐨𝐧𝐦𝐞𝐧𝐭𝐚𝐥 𝐢𝐬𝐬𝐮𝐞𝐬 and social change call for urgent, 𝐜𝐨𝐥𝐥𝐞𝐜𝐭𝐢𝐯𝐞 𝐚𝐜𝐭𝐢𝐨𝐧 toward sustainability.