How can i read and write to cells in the same function?

I am creating a discord bot and I have 2 issues.

Issue One:

In my script i am trying to get the users response to :

interaction.options.get('steamid').value;

and store it in the variable userInput.

Once stored i want to write the stored response to my google sheet in sheet BOTDATA!H1.

The code works when i set const userInput = interaction.options.get('steamid').value; inside the function. Only when i use the ‘/checkbl’ command. If i use any other command i receive an error.

Issue Two: Any command that i use, regardless if it is the ‘/checkbl’ command or not will write `sample value` to the sheet BOTDATA!H1.

This is my current script:

async function blackList() { 
    const sheets = google.sheets({ version: "v4", auth });
    const spreadsheetId = "1lEB9fEqZUNtR0Tq-gzHVVaQ2eQvxsuiwXSTW3VGC2xw";
  
    const sheetName = "BOTDATA";
    const cells = ["H1"];
    const valueInputOption = "USER_ENTERED";
    const userInput = "sample value";
    const result = await sheets.spreadsheets.values.update({
      spreadsheetId,
      range: `'${sheetName}'!${cells[0]}`,
      resource: { values: [[userInput]] },
      valueInputOption,
    });
    console.log(result.data);
    
  }
  
  blackList();

  (async()=>{

if (interaction.commandName === 'checkbl') {
    const userInput = interaction.options.get('steamid').value;
    const bl = new EmbedBuilder()
    .setTitle('Blacklist Checker')
    .setDescription(`${userInput} is`)
    .setColor('Red')
    .setThumbnail('https://i.imgur.com/9GKhYQf.png')
    .setFooter({text: 'DroneOS', iconURL: 'https://i.imgur.com/9GKhYQf.png'})
    .setTimestamp()

    interaction.reply({ embeds: [bl]});

}

})()

I would like to solve both my issues stated above. Along side this i would like ‘userInput’ to write to cell H1 and i want to read cell H2 in the same function. This way i can set the response to:

.setDescription(`${userInput} is ${H2}`)

on my discord bot. Thanks for any help.