I solved like that:

I created a job:

OperationImportJob.php

<?php

namespace App\Jobs;

use Illuminate\Bus\Queueable;
use Illuminate\Queue\SerializesModels;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Maatwebsite\Excel\Facades\Excel;
use App\Imports\OperationImport;

class OperationImportJob implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    protected $file;
    /**
     * Create a new job instance.
     *
     * @return void
     */
    public function __construct($file)
    {
        $this->file = $file;
    }

    /**
     * Execute the job.
     *
     * @return void
     */
    public function handle()
    {
        Excel::import(new OperationImport(), $this->file);
        echo "Import finished.";
    }
}

I modified OperationController.php

/**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function import(Request $request)
    {
        $file = $request->file('import');
        $file = $request->file('import')->store('temp');
        $path = storage_path('app') . '/' . $file;
        dispatch(new OperationImportJob($path));
        return back()->withStatus(__('Operations successfully queued and will be imported soon.'));
    }

I removed ShouldQueue but i keep WithChunkReading on OperationSheetImport.php

<?php

namespace App\Imports;

use App\Operation;
use Illuminate\Support\Collection;
use Maatwebsite\Excel\Concerns\ToCollection;
use Maatwebsite\Excel\Concerns\WithChunkReading;
use Maatwebsite\Excel\Concerns\WithHeadingRow;

class OperationSheetImport implements ToCollection, WithHeadingRow, WithChunkReading
{

    public function headingRow(): int
    {
        return 5;
    }
    /**
     * Transform a date value into a Carbon object.
     *
     * @return \Carbon\Carbon|null
     */
    public function transformDate($value, $format = 'Y-m-d')
    {
        try {
            return \Carbon\Carbon::instance(\PhpOffice\PhpSpreadsheet\Shared\Date::excelToDateTimeObject($value));
        } catch (\ErrorException $e) {
            return \Carbon\Carbon::createFromDate($format, $value);
        }
    }

    public function collection(Collection $rows)
    {
        foreach ($rows as $row) {
            if (empty($row['date'])) {
                break;
            }

            Operation::firstOrCreate([
                'record' => $this->transformDate($row['date'], 'd/m/Y'),
                'value' => $this->transformDate($row['valeur'], 'd/m/Y'),
                'description' => $row['libelle'],
                'debit' => round($row['debit'] ? abs($row['debit']) : 0, 2),
                'credit' => round($row['credit'] ? abs($row['credit']) : 0, 2)
            ]);
        }
    }

    public function batchSize(): int
    {
        return 100;
    }

    public function chunkSize(): int
    {
        return 100;
    }
}

I did not modified OperationImport.php

<?php

namespace App\Imports;

use Maatwebsite\Excel\Concerns\WithMultipleSheets;
use App\Imports\OperationSheetImport;
use Maatwebsite\Excel\Concerns\SkipsUnknownSheets;

class OperationImport implements WithMultipleSheets, SkipsUnknownSheets
{

    public function sheets(): array
    {
        return [
            1 => new OperationSheetImport(),
        ];
    }

    public function onUnknownSheet($sheetName)
    {
        info("Sheet ($sheetName) was skipped");
    }
}